The following projects will be pursued during the coming year: (1) Study of the role of Zn ions in DNA synthesis, with emphasis on the relationship between Zn ions and the requirement of RNA synthesis for DNA synthesis. (2) Kinetics of DNA synthesis in growing and inhibited cells. This will include studies on isolated nuclei and measurements of the enzymes particular to DNA synthesis. (3) The mechanism of stimulation of DNA synthesis by sublethal concentrations of metal ions with emphasis on membrane effects. (4) Studies on the mechanism of glucose transport and its altered status in virus transformed cells. (5) Further characterization of the overgrowth stimulating factors released from transformed cells, and obtained by disruption of normal cells.